Do We Know

?

(How Much)

Q-1

• Who had a flair for working with lenses and discovered the basic instrument of microbiology

• A. Robert Koch• B. Joseph Lister• C. Antony Van Leuuewenhoek• D. Christian Gram

Microscope

•Antony van leeuwenhoek – father of microbiology

•Draper•Developed interest in lens making from glass and observing things through them

•Little animalcules

Q-2

• Identify the gentleman

Vaccination

•Milkmaids who had occupational exposure to cow pox did not get small pox

•Edward Jenner • observed that when extract from cowpox lesion was injected into a person unaffected by small pox, it gave immunity

Q-3

• Which branch of microbiology deals with blood grouping?

• A. immunology• B. serology• C. Virulogy• D. Antigen-antibody reactions

Serology

•Study of these antibodies and antigens in body fluids

•Blood grouping

Q-4

• Which among the following statements is true?

• A. Fungi are eukaryotes • B. viruses have cell wall• C. Bacteria have nucleus• D. Parasites are prokaryotes

Classification of Microorganisms

• Classification by structure• Subcellular – DNA or RNA surrounded by a

protein coat – viruses

• Prokaryotic – simple cell structure with no nucleus or organelles – bacteria

• Eukaryotic – complex cell structure with nucleus and specialized organelles – protozoans, fungi, parasites

• Protozoans – single celled eukaryotes

• Fungi – multicelled eukaryotes with cell wall

• Parasites – multicelled eukaryotes without cell wall

Classification of Microorganisms

• Structure

Q-5

• Which class of organism causes the following illness

• A. Virus• B. Bacteria• C. fungi• D. Protozoa

Protozoans

• Single-celled eukaryotic organisms, larger than bacteria

• Found in soil and water

• Illnesses • Malaria• Amebic dysentery• Trichomoniasis vaginitis

• Leading cause of death in developing countries

Q-6

• What is the type of culture seen in next picture used for?

• A. Antibiotic Specificity Testing• B. Antibody Sensitivity testing• C. Growing in pure culture• D. Antibiotic sensitivity testing

Determining Antimicrobial Sensitivity

Q-7

• What is the unit of measurement of a bacterium cell wall?

• A. meter• B. Nanometer• C. Micrometer• D. centimeter

Size of Bacteria

• Unit of measurement in bacteriology is the micron (micrometre, µm)

• 1 micrometre (10-6)= 1/1000 mm = 1/10000 cm = 1/100000 metre

• 1 nanometer (10-9)= 1/1000 micrometer = 1/100000000 meter

• Bacteria of medical importance• 0.2 – 1.5 µm in diameter• 3 – 5 µm in length

Anatomy of a Bacterial Cell

CELL WALL• Outermost layer, encloses cytoplasm

1.Confers shape and rigidity

2.10 - 25 nm thick

3.Composed of peptidoglycan

Q-8

• What is the process of reproduction of bacteria known as?

• A. replication• B. regeneration• C. duplication• D. Binary fission

Binary Fission• DNA replication• Plasma membrane invaginate• Cell wall deposited in invaginated

space• Cross wall completed• Cells separate

Binary Fission• Light micrograph

Binary Fission

Consequences of Binary Fission• Very large number of cells very fast• Mathematical progressions

• arithmetic (1>2>4>6>8>10>12>14>16)

• geometric(1>2>4>8>16)• exponential expression (20 > 21 > 22

>23>24)• logarithmic expression(0

>log21>log22>log23>log24)

Q-9

• During which phase of bacterial growth curve, is the growth fastest?

• A. Lag phase• B. Log phase• C. Death phase• D. Stationary phase

Bacterial Growth Curve

1 5 10Time (hours)

Lag phase

Log phase

Stationary phase

Death phase

Final question…Thank God!

• Which type of liquid culture medium contains an inhibitory substance added to it?

• A. Enriched Media• B. Enrichment Media• C. Selective Media• D. Indicator Media

Enriched mediaEnriched media• Substances like blood, serum, egg Substances like blood, serum, egg

are added to the basal medium.are added to the basal medium.• Used to grow bacteria that are Used to grow bacteria that are

exacting in their nutritional needs.exacting in their nutritional needs.• Eg: Blood agar, Chocolate agarEg: Blood agar, Chocolate agar

Blood agar Chocolate agar

Enrichment media Enrichment media • Liquid media used to isolate Liquid media used to isolate

pathogens from a mixed pathogens from a mixed culture.culture.

• Media is incorporated with Media is incorporated with inhibitory substances to inhibitory substances to suppress the unwanted suppress the unwanted organism.organism.

• Eg: Eg: • Selenite F Broth Selenite F Broth – for the – for the

isolation of Salmonella, isolation of Salmonella, Shigella Shigella

• Alkaline Peptone Water Alkaline Peptone Water – for – for Vibrio choleraeVibrio cholerae

Selective mediaSelective media• The inhibitory substance is added to a The inhibitory substance is added to a

solid media.solid media.

Eg:Eg:• Mac Conkey’s mediumMac Conkey’s medium for gram for gram

negative bacterianegative bacteria• TCBS TCBS – for V.cholerae– for V.cholerae• LJ mediumLJ medium – M.tuberculosis – M.tuberculosis• Wilson and Blair mediumWilson and Blair medium – S.typhi – S.typhi• Potassium tellurite mediumPotassium tellurite medium – –

Diphtheria bacilliDiphtheria bacilli

TCBSMac Conkey’s medium

Potassium Tellurite media LJ media

Indicator mediaIndicator media• These media contain an indicator These media contain an indicator

which changes its colour when a which changes its colour when a bacterium grows in them.bacterium grows in them.

• Eg: Eg: • Blood agarBlood agar• Mac Conkey’s mediumMac Conkey’s medium• Christensen’s urease mediumChristensen’s urease medium

Urease mediumUrease medium

Hope u enjoyed